To test how deep the water is, simply throw in a stone. People who brag about themselves are like a stone hitting shallow water; they make a big splash. Modest people are always silent, just like a stone thrown into deep water.
你要知道河水深不深， 丢个石子进去，看看河水深不深。喜欢卖弄的人， 就像石子丢在浅水处，会激起浪花； 谦虚的人， 就像石子丢在深水中，是没有声音的。
– Master Jun Hong Lu, Words of Wisdom Volume 2